The unreal is more powerful than the real, because nothing is as perfect as you can imagine it, because it's only intangible ideas, concepts, beliefs, fantasies that last. Stone crumbles, wood rots. People, well, they die. But things as fragile as a thought, a dream, a legend, they can go on and on.
If you knew that your life was merely a phase or short, short segment of your entire existence, how would you live? Knowing nothing 'real' was at risk, what would you do? You'd live a gigantic, bold, fun, dazzling life. You know you would. That's what the ghosts want us to do - all the exciting things they no longer can.